A safety gate for use inside of a house may be placed at the top or bottom of a staircase to prevent children from falling down the staircase or from climbing up and then falling down. Adults, however, must also open up and close the safety gate. Hence it may be advisable to incorporate into the gate a latch mechanism that is easy for an adult to operate but difficult for a child to operate.
It may also be advisable to have an ergonomic latch. Ergonomics may be defined as follows:                Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.        
An ergonomical system, machine or thing may have an easy to use interface. When ergonomics is taken into account, repetitive strain injuries and musculoskeletal disorders may be minimized.
An example of an ergonomic fit is a baseball glove conforming to the right or left hand. A greater ergonomical challenge is to design a piece of equipment for a user who may interact with the equipment with either the right or left hand or both hands. A still greater ergonomical challenge is to design a piece of equipment that by its structure discourages for safety purposes use by a child but that an adult may interact with easily.